The land rush for mobile patents is so feverish that about one-quarter of all patents issued in the U.S. this year will be mobile-related, according to a study released on Wednesday.

"It just shows, given the number of filings, how competitive that space has become," said Chetan Sharma, founder and president of Chetan Sharma Consulting. He studied statistics about patent applications and grants in Europe and the U.S. over the past 20 years. Sharma's study didn't consider the significance of the patents.

The number of mobile-related patents issued annually in the U.S. grew 591 percent between 2002 and 2012, a period in which the U.S. took away the lead in mobile patents from Europe, Sharma said. Last year, the U.S. Patent and Trademark Office granted nearly three times as many mobile patents as the European Patent Office. The U.S. has taken the lead partly because of the growing importance of mobile software development, which takes place predominantly in the U.S., he said.

Samsung Electronics now has the most mobile-related patents across the U.S. and Europe, according to Sharma. Its cumulative total passed Nokia's last year, partly because many of Nokia's older patents from more than 17 years ago expired, he said. But Samsung also had the most patents granted in 2012. They were granted for innovations in devices as well as in network infrastructure and other technologies, Sharma said.

IBM, not a marquee name in mobile, is in second place for both total patents and the number issued last year. The company is contributing to mobile mostly in software, with tools for back-end functions such as database processing and image processing, Sharma said. In cumulative totals, Microsoft comes in third and Nokia has fallen to fourth place, with Sony in fifth.

Despite their mobile OS dominance, neither Apple nor Google is near the top of the patent rankings. That's partly because both are comparatively new to mobile, Sharma said. Even counting its recently acquired Motorola division, Google's patent war chest falls short of the top patent holders and of old-line cellular vendors Ericsson and Alcatel-Lucent. Facebook, which has been criticized in some quarters for not focusing enough on mobile, came in 51st on Sharma's list of the top 65 mobile patent holders across the U.S. and Europe.

Sharma also ranked the top 20 mobile patent holders in the U.S. based on their recent volume of patent filings, which are likely to bring them new patents in the coming years. About 40 percent to 50 percent of all patents applied for are granted, he said. "IBM, Samsung and Microsoft have the healthiest pipeline of intellectual property for the next 5-10 years," he wrote in the report.

The growth in mobile patents doesn't mean the court battles that have rocked the mobile industry over the past few years will keep escalating, Sharma said. He thinks more vendors will start settling their disputes through cross-licensing agreements in the next three to four years and the patent wars either have already peaked or will soon. "It won't go on forever," Sharma said.